Projection type display devices (projectors) to date are typically connected via a video cable to an image generating device, for example, a video cassette recorder or computer. A computer-generated analog RGB signal is input to the projector via a video cable and rendered as an image on a screen or the like. However, conventional projectors function as simple stand-alone projectors.
With expansion of networks in recent years, there have been developed technologies for shifting the bulk of processing to server computers in order to reduce the load on client computers. In application service provider (ASP) technologies, for example, an application program (hereinafter “application”) requested is run on the server computer, and the results are transmitted to the client as HTML data or as display screen data in a proprietary format. With ASP technology, the client merely runs a client application and displays on its display a user interface (display screen information) in response to the received display screen data. Thus, relatively few functions are required of a client, allowing it to function as a so-called “thin client.”
Another development seen in recent years has been the increasing use of projectors for presentations at conferences and the like. Permanent projector installations in individual conference rooms are no longer rare.
This state of affairs has led to a desire to connect projectors to networks. However, to date projectors have been designed on the assumption that they will be connected to a local computer, and thus network hookups have required the agency of a computer. This requires providing one computer for each projector one wishes to connect to the network, posing a problem of inefficiency. Further, the computer and projector must be connected by a cable each time they are used, which obviates the convenience associated with networks. Another problem is that larger numbers of computers require more management resources. Also, additional convenience could be provided if projectors could function as terminal devices at ASPs.